The Square Kilometre Array (SKA) will be the world's largest radio interferometer by far. Its thousands of antennas, with up to one square kilometer of collecting area, will be distributed across thousands of kilometres and numerous stations. The SKA will constitute a continental-scale sensor network, needing for its operation exascale computation systems running over exabytes of data. In order to embrace the Big Data challenge posed by this copious data flux, astronomers will need tools so that enable them to embed their algorithms within the SKA processing stream, and provide services than can be later reused by the community. Given the need to perform multiple, geographically distributed computations on data streams generated by a widely distributed sensor network, e-Science tools are a particularly good fit. In this talk we will show how scientific workflow technologies are very well suited for this task, as they provide a formal definition of processes, inputs and outputs. This allows for their inclusion in more general scientific processing systems, exploiting their parallelism, and recording the provenance for processes and results. The developments of the AMIGA group (Analysis of the interstellar Medium of Isolated GAlaxies) within the Wf4Ever FP7 project (http://amiga.iaa.es/p/212-scientific-workflows.htm) will be presented. AMIGA aims to provide scientific workflows for the 3D analysis and modelling of HI data, which can be shared and composed within the Virtual Observatory framework.